The United Nations Conference on Sustainable Development (Rio+20) ended last Friday (22 June) with an international agreement on the need for all countries to commit themselves to achieving sustainable development. The agreement immediately came under fire from several quarters for its lack of detail about how this will be done, and the absence of new financial commitments from the developed world.

Critics in the scientific and technical communities also said it lacked adequate recognition of the importance of science in achieving sustainable development, and details of mechanisms for facilitating the technology transfer needed to make this possible.

But the agreement could lead to a stronger interface between science and policy. And voluntary pledges announced outside the formal proceedings of the conference could, if fulfilled, significantly boost sustainable technology in the developing world.

Science at Rio+20 - Some 188 heads of state and government, as well as ministers, had assembled for three days (20-22 June) at Rio+20 in Brazil to endorse the 53-page outcome document, The Future We Want. The summit differed in important respects from its predecessor, the 1992 UN Conference on Environment and Development (UNCED), or Earth Summit, also held in Rio de Janeiro.

Unlike the earlier meeting, the outcome was intended to be a broad statement of intent, with no legal status, and was never officially expected to include commitments to new funding.

Instead, Rio+20's goal was to address ways of implementing the sustainable development agenda that was agreed in 1992 but remains largely unfulfilled, as well as tackling environmental, social and economic issues that have emerged since then. On several issues, the document left the science and engineering communities dismayed.

For example, scientists had hoped that the text would express urgency over the accumulated evidence that many of the planet's systems are now under dangerous stress, threatening, for example, fish numbers and terrestrial food chains.

But it proved impossible to reconcile such a statement, and its implied support for limiting economic growth, with the goal's paramount goal - namely, how to raise more than one billion people out of extreme poverty, a task for which many claim economic growth remains essential. As a result, the outcome is likely to be "sustainable development as usual", rather than action on the scale that the scientific evidence now demands, said Gisbert Glaser, senior advisor at the International Council for Science (ICSU).

Research communities also complained that science was not given the same prominence as a critical component of sustainable development solutions as it had been in documents generated by the 1992 summit. In particular, no section of the final document includes the word "science" in its title.

"We simply don't understand why the document does not have a section on science. This lack sends a very unfortunate message to the global science community and its sponsors," said Steven Wilson, ICSU's executive director. However, the agreement does provide a number of openings to enable the better integration of science into policymaking.

In particular, nations have "invited" the UN General Assembly to "upgrade" and "strengthen" the Nairobi-based UN Environment Programme (UNEP), a process that is likely to provide the programme with more secure funding and universal membership. Currently, UNEP relies on mostly voluntary contributions and a governing council made up of 58 UN members states.

The changes to UNEP will include a stronger science/policy interface in order to improve evidence-based decision-making. UNEP will also disseminate evidence-based environmental information, provide capacity building to countries, and support and facilitate access to sustainable technology.

The meeting also decided to replace the Commission on Sustainable Development (CSD) - a body set up in 1992 to ensure effective follow-up to the first Earth Summit - with a 'high-level political forum,' which will have greater powers to ensure adherence to sustainable development commitments.

The Future We Want says the new forum "could" strengthen the science/policy interface "through review of documentation bringing together dispersed information and assessments ... in the form of a global sustainable development report".

And nations have agreed to initiate a process leading to the creation of Sustainable Development Goals (SDGs), in which the scientific community will be "fully involved". The document's frequent references to the need for capacity building in science in developing countries will put pressure on governments, science funders and UN organisations to do more in this regard, said Glaser.

However several references in the document to the importance of technology in helping developing countries meet their economic, social and environmental needs have been criticised on two fronts.

Overall, according to a number of NGOs, these references give the impression that many problems of sustainability can be solved with "technological fixes". In contrast - and unmentioned in the document - recent thinking within global change research communities has led them to re-cast their programmes as multidisciplinary enterprises more suited to tackling the complex problems inherent in achieving a green economy. "There is good, supporting language on technology [in the final text] which we fully support," said Glaser.

"But we also need new knowledge for the green economy - for example [that which comes from the] social sciences, behavioural science, and understanding of consumption patterns. And there is nothing in the text that says we need that new knowledge."

A second criticism was that there was no agreement on ways of delivering technology transfer through non-market mechanisms (an international fund, for example). This sentiment was expressed particularly strongly by the Group of 77 (a loose coalition of developing nations designed to promotes its members' collective economic interests at the UN).

On this issue, the text merely asks the UN to identify possible steps for improving developing countries' access to clean technologies, and to make recommendations to its 67th General Assembly, taking place in September this year. The text has "glossed over" key issues for developing countries, including the financing of technology transfer, said Quamrul Chowdhury, principal negotiator for the G77+China group.

On a more promising note, from the negotiations' outset, Rio+20's secretary-general, Sha Zukang, had asked governments, development banks, the corporate sector and civil society groups to register voluntary commitments as a way of bypassing the challenges of multilateral agreements.

By Friday night, the "compendium of commitments" numbered 692 promises, with an estimated $513 billion mobilized from the 13 largest commitments. Some of this money will be used to finance the use of more sustainable technologies, including a major commitment by a consortium of development banks to finance sustainable transport.

'Sustainable Energy For All', a project launched by UN secretary-general, Ban Ki-moon, which aims to achieve, by 2030, targets in energy access and efficiency, and in renewable energy, received commitments worth more than US$50 billion from businesses and investors.

The UN announced that more than 50 governments from Africa, Asia, Latin America and Small Island Developing States are developing energy plans and programmes. Commenting on the overall outcome of Rio+20, Helena Nader, president of the Brazilian Association for the Advancement of Science, said she was disappointed with the final document.

"It is weak - not focused - with important gaps," Nader said, adding that it did not adequately reflect the large amount of work put into producing it. "It is a backward step. Science is almost nonexistent throughout the document," she said.

Achim Steiner, UNEP's executive director, admitted that many scientists would see the outcome document as having failed to "[change] our trajectory for the coming years". But the document had a "hidden richness that will allow many activities to go forward", he added.